Directional transmission techniques

ABSTRACT

Embodiments provide techniques for the transmission of broadcasts. For instance, an apparatus may include a sequence selection module, and multiple radiating elements. The sequence selection module selects sequences of directional transmission patterns, where each selected sequence corresponds to a time period. The multiple radiating elements wirelessly transmit a broadcast at the time periods in accordance with the selected sequences. The broadcast may include, for example, beacons, and/or a data broadcast, and/or a control broadcast and/or a management broadcast.

This application claims priority to U.S. application Ser. No.12/315,057, filed on Nov. 25, 2008.

BACKGROUND

Wireless networks, such as wireless personal area networks (WPANs),wireless local area networks (WLANs), and/or piconets may employtransmissions called beacons. Beacons, which are typically transmittedby central controller nodes, allow client devices to discover,synchronize and associate with a corresponding network.

To reach all client devices, beacons are primarily transmitted in anomni-directional mode. However, some communications systems employdirectional wireless transmission techniques. For such systems, multipledirectional beacon transmissions in different directions can be made.Through such multiple transmissions, omni-directional (or quasiomni-directional) coverage can be achieved through a sequence ofdirectional transmissions.

In dense environments having several nearby simultaneous operatingwireless networks, the sequence in which such multiple directionalbeacon transmissions are performed may have a significant impact on thenetwork's robustness. For example, certain sequences may result inbeacons colliding with transmissions of a nearby network. Thus, thedirectional transmission sequences employed by a network may affect theability of devices to discover, synchronize and associate with thenetwork.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference numbers generally indicate identical,functionally similar, and/or structurally similar elements. The drawingin which an element first appears is indicated by the leftmost digit(s)in the reference number. The present invention will be described withreference to the accompanying drawings, wherein:

FIG. 1 is a diagram of exemplary transmission sectors;

FIG. 2 is a diagram of an exemplary time division multiple access (TDMA)format;

FIG. 3 is a diagram of an exemplary operational environment;

FIG. 4 is a timing diagram;

FIG. 5 is a diagram of an exemplary network controller implementation;

FIG. 6 is a diagram of an exemplary antenna module implementation;

FIG. 7 is a diagram of an exemplary logic flow.

DETAILED DESCRIPTION

Embodiments provide techniques for directional transmissions. Forinstance, an apparatus may include a sequence selection module, andmultiple radiating, elements. The sequence selection module selectssequences of directional transmission patterns, where each selectedsequence corresponds to a time period. The multiple radiating elementswirelessly transmit a broadcast at the time periods in accordance withthe selected sequences. The broadcast may include, for example, beaconsand/or a data broadcast.

Through the employment of such sequences, the probability of recurringtransmission collisions may be reduced. Thus, embodiments mayadvantageously improve robustness of wireless networks.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, appearances of the phrases “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments.

As described above, existing wireless networks provide firomni-directional broadcast transmissions. Such broadcast transmissionsmay include beacons, which allow client devices to discover,synchronize, and associate with a network. Also, such broadcasttransmissions may include data transmissions. Embodiments, however, arenot limited to these exemplary broadcast transmissions.

The techniques described herein may be employed in various types ofnetworks. Examples of such networks include Institute of Electrical andElectronic Engineers (IEEE) 802.15 wireless personal area networks(WPANs), such as Bluetooth networks. Also, these techniques may beemployed with IEEE 802.11 wireless local area networks (WLANs). Furtherexemplary networks include IEEE 802.16 wireless metropolitan areanetworks (WMANs), such as WiMAX networks. WiMAX networks may supportdirectional transmissions through beamforming capabilities. Also, thetechniques described herein may be employed in 60 GHz networks. Thesenetworks are provided as examples, and not as limitations. Accordingly,the techniques described herein may be employed with other networktypes.

In networks having directional communication capabilities, multipledirectional transmissions may be employed to provide omni-directionalbroadcast support. Thus, for a device that supports M directions, abeacon broadcast transmission may be achieved through M transmissions ofthe beacon frame e.g., one transmission for each supported direction).

An example of this feature is provided in FIG. 1, which shows (from aplan perspective) exemplary transmission sectors for a networkcontroller 102. In particular, FIG. 1 shows eight sectors (S₀ throughS₇). These sectors are each within an available transmission panorama103. For purposes of illustration, available transmission panorama 103encompasses a full rotation (i.e., 360 degrees) around networkcontroller 102. However, panoramas of other extents may alternatively beemployed.

To broadcast a frame, network controller 102 transmits the frame eighttimes. More particularly, network controller 102 sequentially transmitsthe frame in each of sectors S₀ through S₇. As described herein, thistechnique may be employed with various types of broadcasts, such asbeacons, data transmissions, and so forth. Although FIG. 1 shows eightsectors, any number of directional transmission sectors ma be employed.Moreover, embodiments may employ patterns other than sectors.

Wireless networks commonly employ multiple access techniques that allowa number of devices to share communications media. One such technique iscarrier sense with multiple access with collision avoidance (CSMA/CA).CSMA/CA allows such sharing through a carrier sensing scheme. Moreparticularly, a device employs carrier sensing before it transmits aframe. The carrier sensing detects whether another signal from a remotedevice is being transmitted. If so, then the device defers transmittingits frame, and waits for a time interval (also referred to as a “backoffdelay”) before re-trying to send the frame.

Alternatively or additionally, wireless networks may employ timedivision multiple access (TDMA) techniques allow such sharing throughthe allocation of unique time slots to each device.

FIG. 2 is a diagram illustrating an exemplary TDMA format 200 for awireless communications network. This allocation involves a repeatingsequence of superframes 202 _(a)-202 _(N). Each of these superframesincludes a beacon period (BP) 204. More particularly, FIG. 2 shows thatsuperframes 202 _(a)-202 _(N) include BPs 204 _(a)-204 _(N),respectively.

BPs 204 _(a-N) provide a network controller node (e.g., a PNC) withresources to transmit beacons. The controller node broadcasts suchbeacons through multiple (designated by an integer M) directionaltransmissions. Accordingly, FIG. 2 shows that each of BPs 204 _(a)-204_(N) includes multiple portions (P₀-P_(M-1)). Each directionaltransmission is sent within a corresponding one of these portionsP₀-P_(M-1). Thus, when TDMA format 200 is employed in the context ofFIG. 1, M=8 because the network controller has eight directionaltransmission sectors.

Although not shown, data slots within superframes 202 _(a)-202 _(N)similarly allow a device e.g., a network controller) to broadcast a datatransmission. Thus, such data slots may also include M portions formultiple directional data transmissions.

A network controller may employ various directional transmissionapproaches in the transmissions of broadcasts (e.g., beacons). Oneapproach uses the same directional transmission sequence for successivesuperframes. Thus, with reference to FIG. 1, directional broadcast frametransmissions for sectors S₀ through S₇ would occur in the same sequencein successive superframes.

However, various problems may occur when the same directionaltransmission sequence is employed for successive time periods. Forinstance, particular directional transmissions within one wirelessnetwork may persistently interfere with particular data communicationsin a nearby wireless network. An example of this problem is describedbelow with reference to FIG. 3.

FIG. 3 is a diagram of an exemplary operational environment 300. In thisenvironment, two simultaneously operating wireless networks are in closeproximity to each other. More particularly, FIG. 3 shows a firstwireless network 302 that is controlled by a network controller 306 a,and a second wireless network 304 that is controlled by a networkcontroller 306 b. Various client devices (CDs) participate in thesenetworks. For instance, FIG. 3 shows devices 308 a and 308 bparticipating in network 302, while devices 308 c and 308 d participatein network 304.

Each of network controllers 306 a and 306 b periodically transmit asequence of beacon transmissions. For instance, at every superframe,network controller 306 a transmits a sequence of individual beacons forsectors S₀ through S₇ (i.e., [S₀, S₁, S₂, S₃, S₄, S₅, S₆, S₇]).

Also, device 308 d is shown sending a data transmission 320 to networkcontroller 306 b. During this data transmission, FIG. 3 shows networkcontroller 306 a sending a beacon transmission 322 corresponding tosector S₅. Although device 308 c lies within sector S₅ of networkcontroller 306 a, it does not receive beacon transmission 322. This isbecause beacon transmission 322 collides with data transmission 320(shown in FIG. 3 as a collision 324). Accordingly, this collisionimpairs or prevents device 308 c from discovering, synchronizing, and/orassociating with network 302.

If a network controller (such as network controller 306 a) alwaysemploys the same sequence of beacon transmissions, it is possible thatone or more of its beacons (and/or other broadcast(s)) will never besuccessfully received by certain device(s). This is because suchtransmissions will collide with a nearby network's scheduledtransmissions (e.g., periodic video streaming, another beacon,beamforming training sequences, etc). Such occurrences may unfortunatelyleave device(s) unable to discover/associate/communicate with thenetwork controller or receive broadcast frames from the networkcontroller for a very long period of time (if at all). Accordingly, thedirectional sequences used for beacons (or other broadcasts) may impactprotocol robustness.

Embodiments provide techniques to avoid such disadvantages. Forinstance, embodiments may change an employed sequence of directionaltransmission patterns from one time period (e.g., superframe) toanother. As a result, embodiments may enhance the robustness andperformance of wireless communications protocols. For example, fewercollisions may occur in simultaneously operating, wireless networkenvironments.

Thus, referring again to FIG. 3, network controller 30 a may employ suchtechniques by using different sequences of directional transmissionpatterns (e.g., different sequences of sectors S₀ through S₇) forsuccessive beacons (and/or other broadcasts). By changing suchsequences, a network controller (e.g., a PNC) can increase thelikelihood that a client device will receive the controller'stransmission when another device is not sending an otherwise interferingtransmission associated with another network.

Embodiments may employ various techniques to change the sequence inwhich broadcast frames are transmitted. For example, embodiments mayemploy random techniques and/or round robin technique(s). However, othertechniques may be alternatively or additionally employed.

When employing a random technique, a device (e.g., a network controller)randomly generates a directional transmission sequence before eachbroadcast (e.g., beacon) is sent. The device then employs this sequenceto send the broadcast.

For example, if a total of M (where M is an integer greater than 0)directions are supported, the device generates a sequence C. C is arandom permutation of the sequence [S₀, S₁, . . . , S_(N-1)]. Thus, byrandomly generating C for successive time periods (e.g., for successivesuperframes), the transmitting device can increase the likelihood thatits broadcasts reach a device without collisions from othertransmissions.

When employing a round robin technique, a sequence of the M directionssupported by a device is rotationally shifted between successive timeintervals (e.g., successive superframes). An example of this shifting isshown in FIG. 4, which shows a sequence 400 of superframes 402 ₀ through402 _(M). Each of these superframes includes a beacon period (BP). Moreparticularly, FIG. 4 shows superframes 402 ₀-402 _(M) having BPs 404₀-404 _(M), respectively.

As shown in FIG. 4, during BP 404 ₀ of superframe 402 ₀, the device usesa directional sequence [S₀, S₁, . . . S_(M-1)]. In superframe 402 ₁, thefirst direction becomes S₁. This results in the directional sequence[S₁, S₂, . . . , S₀]. Accordingly, in superframe the sequence becomes[S_(M-1), S₀, . . . , S_(M-2)].

Together, superframes 402 ₀ through 402 _(M-1) constitute a sequence ofsuperframes that is referred to herein as a round. In a given round,each of the M directions be first in a directional sequence. Once thisoccurs, a next round is started. Accordingly, FIG. 4 shows a round 406 ₁following a round 406 ₀.

The directional transmission techniques described herein may be employedfor various types of transmissions. The above examples involve beacontransmissions and data broadcasts. However, the disclosed techniques maybe employed other types of transmissions. For instance, exemplarytransmissions include (but are not limited to) data frames, managementframes, and control frames. In embodiments, such frames may bebroadcasted. Accordingly, multiple frames (e.g., consecutive frames) mayemploy different sequences of directional transmission patterns, asdescribed herein.

Data frames carry protocols and data from higher layers within the framebody. Accordingly, data frames may convey payload information associatedwith one or more applications.

Management frames enable stations to establish and maintaincommunications. In the context of IEEE 802.11 networks, managementframes include authentication frames, deauthentication frames,association request frames, association response frames, reassociationrequest frames, reassociation response frames, disassociation frames,beacon frames, probe request frames, and probe response frames.

Control frames assist in the delivery of data frames between stations.Exemplary IEEE 802.11 control frames include Request to Send (RTS)frames, Clear to Send (CTS) frames, and Acknowledgement (ACK) frames.

FIG. 5 is a diagram of an implementation 500 that may be included in anetwork controller. As shown in FIG. 5, implementation 500 may includean antenna module 502, a transceiver module 504, and a host module 506.These elements may be implemented in hardware, software, or anycombination thereof.

Antenna module 502 provides for the exchange of wireless signals withremote devices. Moreover, antenna module 502 may transmit wirelesssignals through one or more directional radiation patterns. Thus,antenna module 502 may include multiple antennas and/or multipleradiating elements e.g., phased-array radiating elements). Detailsregarding exemplary implementations of antenna module 502 are describedbelow with reference to FIG. 6.

Transceiver module 504 provides an interface between antenna module 502and host module 506. For instance, transceiver module 504 receivessymbols 520 from host module 506 and generates corresponding signals 522for wireless transmission by antenna module 502. This may involveoperations, such as modulation, amplification, and/or filtering.However, other operations may be employed.

Conversely, receiver portion 510 obtains signals 524 received by antennamodule 502 and generates corresponding symbols 526. In turn, receiverportion 510 provides symbols 526 to host module 506. This generation ofsymbols 526 may involve operations, including (but not limited to)demodulation, amplification, and/or filtering.

The symbols exchanged between host module 506 and transceiver module 504may form messages or information associated with one or more protocols,and/or one or more user applications. Thus, host module 506 may performoperations corresponding to such protocol(s) and/or user application(s).Exemplary protocols include various media access, network, transportand/or session layer protocols. Exemplary user applications includetelephony, messaging, e-mail, web browsing, content (e.g., video andaudio) distribution/reception, and so forth.

In addition, host module 506 may exchange control information 540 withtransceiver module 504. This control information may pertain to theoperation and status of transceiver module 504. For instance, controlinformation 540 may include directives that host module 506 sends totransceiver module 504. Such directives may establish operatingparameters/characteristics for transceiver module 504. Also controlinformation 540 may include data (e.g., operational status information)that host module 506 receives from transceiver module 504.

FIG. 5 shows that transceiver module 504 includes a transmitter portion508, a receiver portion 510, a control module 512, a sequence selectionmodule 514, a directional control module 516, and a storage module 518.These elements may be implemented in hardware, software, or anycombination thereof.

Transmitter portion 508 generates signals 522 from symbols 520.Conversely, receiver portion 510 generates symbols 526 from receivedsignals 524. To provide such features, transmitter portion 508 andreceiver portion 510 may each include various components, such asmodulators, demodulators, amplifiers, filters, buffers, upconverters,and/or downconveters. Such components may be implemented in hardware(e.g., electronics), software, or any combination thereof.

Signals 522 and 524 may be in various formats. For instance, thesesignals may be formatted for transmission in IEEE 802.11 IEEE 802.15,and/or IEEE 802.16 networks. However, embodiments are not limited tothese exemplary networks be employed.

Control module 512 governs various operations of transceiver module 504.For instance, control module 512 may establish operationalcharacteristics of transmitter portion 508 and receiver portion 510.Such characteristics may include (but are not limited to timing,amplification, modulation/demodulation properties, and so forth. Asshown in FIG. 5 the establishment of such characteristics may beimplemented in directives 528 and 530, which are sent to transmitterportion 508 and receiver portion 510, respectively.

In addition, control module 512 governs the employment of directionaltransmission features. In particular, FIG. 5 shows control module 512generating an initiation signal 532 and a trigger signal 534. Thesesignals control actions of sequence selection module 514 and directionalcontrol module 516.

More particularly, upon activation of initiation signal 532, sequenceselection module 514 generates a directional sequence 536 that indicatesa sequence of directional transmission patterns to be employed byantenna module 502. Sequence selection module 514 may generate thissequence in accordance with various techniques (e.g., random, roundrobin, and so forth).

In embodiments, control module 512 may activate initiation signal 532each time a new sequence of directional transmission patterns is to beemployed. For example, as described herein, control module 512 mayactivate initiation signal 532 at each superframe. However, otherschemes for activating initiation signal 532 may be employed.

As shown in FIG. 5, directional sequence 536 is sent to directionalcontrol module 516. In turn, directional control module 516 establishesoperational characteristics for antenna module 502 that correspond todirectional sequence 536. As shown in FIG. 5, this may involveconfiguring antenna module 502 with configuration parameters 542.

Configuration parameters 542 may specify particular parameters to beapplied to each antenna and/or radiating element within antenna module502. Examples of such parameters include (but are not limited to)amplification gains, attenuations factors, and/or phase shifts values.In embodiments, configuration parameters 542 include multiple parametersets. Each of these sets includes one or more parameters for adirectional transmission pattern specified in directional sequence 536.

Directional control module 516 configures antenna module 502 in responseto trigger signal 534 (which is received from control module 512). Thismay involve trigger signal 534 controlling the delivery of parametersets so antenna module 502 may employ them in synchronization withcorresponding directional transmissions within a broadcast.

In embodiments, directional control module 516 may obtain configurationparameters 542 from storage module 518. This feature is shown in FIG. 5as parameter values 538. Thus, storage module 518 may store informationpertaining to a plurality of directional transmission patterns. Forexample, storage module 518 stores sets of operational parameters thatare indexed in accordance with the indexing scheme employed bydirectional sequence 536. Examples of such storage media are providedbelow.

FIG. 6 is a diagram showing an exemplary implementation of antennamodule 502. As shown in FIG. 6, this implementation includes multipleradiating elements 602 a-n, multiple processing nodes 604 a-n, asplitter module 606, and an interface module 608. These elements may beimplemented in hardware, software, or any combination thereof.

Each radiating element 602 may be a distinct antenna. Alternatively oradditionally, each radiating element 602 may be a radiating elementwithin a phased-array or switched-beam antenna. Thus, together,radiating elements 602 a-n may form one or more distinct antennas,and/or one or more phased arrays, and/or one or more switched beamantennas. As shown in FIG. 6, radiating elements 602 a-n are eachcoupled to a corresponding one of processing nodes 604 a-n.

As shown in FIG. 6, splitter module 606 receives signal 522 (which isgenerated by transceiver module 504 of FIG. 5). Upon receipt, splittermodule 606 “splits” signal 522 into substantially identical inputsignals 620 a-n. This splitting may occur with some degree of insertionloss. Input signals 620 a-n are sent to processing nodes 604 a-n,respectively.

Processing nodes 604 a-n generate processed signals 622 a-n from inputsignals 620 a-n, respectively. In turn, processed signals 622 a-n aresent to radiating elements 602 a-n, respectively. In generatingprocessed signals 622 a-n, processing nodes 604 a-n may perform variousoperations cm input signals 620 a-n.

Examples of such operations performed by processing nodes 604 a-ninclude (but are not limited to attenuation, amplification, and/or phaseshifting. Switching is a further exemplary operation. For example, oneor more of processing nodes 604 a-n may selectively pass or block theircorresponding input signal(s) 620. Thus, when an input signal 620 isblocked, its corresponding output signal 622 may be a zero energy(nulled) signal.

The manner in which processing nodes 604 a-n generate processed signals622 a-n is determined by control signals 624 a-n, respectively. Thus,these signals may convey attenuation factors, amplification gains, phaseshift values, switching directives, and so forth.

In embodiments, control signals 624 a-n are included in configurationparameters 542, which are received by interface module 608. Theseparameters may be received in various formats (e.g., analog, digital,serial, parallel, etc.). Interface module 608 extracts these parametersand formats them as control signals 624 a-n. As described above, controlsignals 624 a-n are sent to processing nodes 604 a-n, respectively.

The implementation of FIG. 6 is shown for purposes of illustration andnot limitation. Accordingly, implementations of antenna module 602 mayinclude other elements. For example, implementations may one or moreamplifiers and/or filters. Such amplifier(s) and/or filters may becoupled between processing nodes 604 a-n and radiating elements 602 a-n.

A broadcast scenario is now described with reference to FIGS. 5 and 6.In this scenario, each of radiating elements 602 a-n is an antennahaving, a particular radiation pattern. For example, the patterns ofradiating elements 602 a-n may respectively correspond to multipletransmission sectors, such as sectors S₀-S₇ of FIG. 1.

Accordingly, in this scenario, processing nodes 604 a-n operate asswitching nodes that may pass or block input signals 620 a-n,respectively. As described above, processing nodes 604 a-n arecontrolled by control signals 624 a-n, respectively. In this case, thesecontrol signals convey binary switching commands (e.g., having statesswitch open or switch close).

Since each of radiating elements 602 a-n corresponds to a particularradiation pattern, control signals 624 a-n may sequentially select oneof processing nodes 604 a-n to be open, and the remaining processingnodes to be closed. Thus, through this selection technique, only ofradiating elements 602 a-n emits a signal at a time.

FIG. 7 illustrates an embodiment of a logic flow. In particular, FIG. 7illustrates a logic flow 700, which may be representative of theoperations executed by one or more embodiments described herein.Although FIG. 7 shows a particular sequence, other sequences may beemployed. Also, the depicted operations may be performed in variousparallel and/or sequential combinations.

The flow of FIG. 7 involves the transmission of a wireless broadcast.This broadcast may convey various forms of information. For instance, inembodiments, the wireless broadcast may be beacons and/or data frames.However, embodiments are not limited to these examples.

At a block 702, a first sequence of a plurality of directionaltransmission patterns is selected. In the context of FIG. 5, this may beperformed by sequence selection module 514. Each of the plurality ofdirectional transmission patterns ma correspond to a sector within anavailable transmission panorama. For instance, the directionaltransmission patterns may correspond to sectors S₀-S₇ of FIG. 1.

At a block 704, the wireless broadcast is sent within a first timeperiod. More particularly, the wireless broadcast is sent within thefirst time period in accordance with the sequence selected at block 702.This first time period may be a first superframe within a TDMAtransmission format.

As shown in FIG. 7, a second sequence of the plurality of directionaltransmission patterns is selected at a block 706. Referring again toFIG. 5, this block may be performed by sequence selection module 514.

At a block 708, the wireless broadcast is sent within a second timeperiod. In particular, the broadcast is sent during the second timeperiod in accordance with the second sequence of directionaltransmission patterns. This second time period may be a secondsuperframe within a TDMA transmission format. For example, the first andsecond superframes may be consecutive superframes.

In the above description, blocks 702 and 706 involve sequences ofdirectional transmission patterns being selected. These selections maybe made in accordance with various techniques, such as random and/orround robin. Embodiments, however, are not limited to these techniques.

As described herein, various embodiments may be implemented usinghardware elements, software elements, or any combination thereof.Examples of hardware elements may include processors, microprocessors,circuits, circuit elements (e.g., transistors, resistors, capacitors,inductors, and so forth), integrated circuits, application specificintegrated circuits (ASIC), programmable logic devices (PLD), digitalsignal processors (DSP), field programmable gate array (FPGA), logicgates, registers, semiconductor device, chips, microchips, chip sets,and so forth.

Examples of software may include software components, programs,applications, computer programs, application programs, system programs,machine programs, operating system software, firmware, software modules,subroutines, functions, methods, procedures, software interfaces,application program interfaces (API), instruction sets, computing code,computer code, code segments, computer code segments, words, values,symbols, or any combination thereof.

Some embodiments may be implemented, for example, using amachine-readable medium or article which may store an instruction or aset of instructions that, if executed by a machine, may cause themachine to perform a method and/or operations in accordance with theembodiments. Such a machine ma include, for example, any suitableprocessing platform, computing platform, computing device, processingdevice, computing system, processing system, computer, processor, or thelike, and may be implemented using any suitable combination of hardwareand/or software.

The machine-readable medium or article may include, for example, anysuitable type of memory unit, memory device, memory article, memorymedium, storage device, storage article, storage medium and/or storageunit, for example, memory, removable or non-removable media, erasable ornon-erasable media, writeable or re-writeable media, digital or analogmedia, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM),Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW),optical disk magnetic media, magneto-optical media, removable memorycards or disks, various types of Digital Versatile Disk (DVD), a tape, acassette, or the like. The instructions may include any suitable type ofcode, such as source code, compiled code, interpreted code, executablecode, static code, dynamic code, encrypted code, and the like,implemented using any suitable high-level, low-level, object-oriented,visual, compiled and/or interpreted programming language.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not in limitation. For example, the directionaltransmission techniques described herein are not limited to networksemploying TDMA. Networks employing, other transmission formats, such asCSMA/CA, and carrier sense multiple access with collision detection(CSMA/CD), may also employ such directional transmission techniques.

Accordingly, it will be apparent to persons skilled in the relevant artthat various changes in form and detail can be made therein withoutdeparting from the spirit and scope of the invention. Thus, the breadthand scope of the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. An apparatus, comprising: a sequence selectionmodule to select first and second sequences of a plurality ofdirectional transmission patterns, each of the plurality of directionaltransmission patterns corresponding to a sector; and a plurality ofradiating elements to: wirelessly transmit, in a first time interval,multiple beacon transmissions in accordance with the first sequence; andwirelessly transmit, in a second time interval, multiple beacontransmissions in accordance with the second sequence.
 2. The apparatusof claim 1, wherein the sequence selection module is to randomly selectbetween the first and second sequences.
 3. The apparatus of claim 1,further comprising: a directional control module to establishoperational characteristics for the plurality of radiating elementsbased on the first and second sequences.
 4. The apparatus of claim 1,further comprising: a host module to perform operations associated withone or more user applications.
 5. The apparatus of claim 1, wherein eachof the first and second sequences encompasses a full rotation panorama.6. The apparatus of claim 1, wherein the plurality of radiating elementsis to wirelessly transmit a data transmission between the first andsecond time intervals.
 7. The apparatus of claim 1, wherein the firsttime interval and second time interval are beacon periods.
 8. Theapparatus of claim 1, wherein the first sequence is different from thesecond sequence.
 9. A method, comprising: selecting a first sequence ofa plurality of directional transmission patterns; sending, in a firsttime period, multiple beacon transmissions in accordance with the firstsequence of the plurality of directional transmission patterns;selecting a second sequence of the plurality of directional transmissionpatterns; and sending, in a second time period, multiple beacontransmissions in accordance with the second sequence of the plurality ofdirectional transmission patterns, wherein the first sequence isdifferent from the second sequence.
 10. The method of claim 9: whereinsaid selecting the first sequence and said selecting the second sequenceare in accordance with a random selection technique.
 11. The method ofclaim 9, wherein each of the plurality of directional transmissionpatterns corresponds to a sector in an available transmission panorama.12. The method of claim 9, wherein the first time period and second timeperiod are beacon periods.
 13. The method of claim 9, further comprisingwirelessly transmitting a data transmission between the first and secondtime periods.
 14. An apparatus, comprising: a sequence selection moduleto select first and second sequences of a plurality of directionaltransmission patterns, each of the plurality of directional transmissionpatterns corresponding to a sector; and a directional control module toestablish operational characteristics for a plurality of radiatingelements based on the first and second sequences, wherein theoperational characteristics are in accordance the first sequence formultiple beacon transmissions in a first time interval; wherein theoperational characteristics are in accordance the second sequence formultiple beacon transmissions in a second time interval.
 15. Theapparatus of claim 14, wherein the sequence selection module is torandomly select between the first and second sequences.
 16. Theapparatus of claim 14, further comprising: a host module to performoperations associated with one or more user applications.
 17. Theapparatus of claim 14, wherein one or more user applications include avideo application.
 18. The apparatus of claim 14, wherein each of thefirst and second sequences encompasses a full rotation panorama.
 19. Theapparatus of claim 14, wherein the plurality of radiating elements is towirelessly transmit a data transmission between the first and secondtime intervals.
 20. The apparatus of claim 14, wherein the first timeinterval and the second time interval are beacon periods.
 21. Theapparatus of claim 14, wherein the first sequence is different from thefirst sequence.
 22. The apparatus of claim 14, further comprising theplurality of radiating elements.
 23. An article comprising anon-transitory machine-accessible medium having stored thereoninstructions that, when executed by a machine, cause the machine to:select first and second sequences of a plurality of directionaltransmission patterns, each of the plurality of directional transmissionpatterns corresponding to a sector; and establish operationalcharacteristics for a plurality of radiating elements based on the firstand second sequences, wherein the operational characteristics are inaccordance the first sequence for multiple beacon transmissions in afirst time interval; and wherein the operational characteristics are inaccordance the second sequence for multiple beacon transmissions in asecond time interval.
 24. The article of claim 23, wherein saidselecting the first sequence and said selecting the second sequence arein accordance with a random selection technique.
 25. The article ofclaim 23, wherein each of the first and second sequences encompasses afull rotation panorama.